can someone pls tell me how often differential fluid has to be changed on this car? is it same everytime with engine oil? So if i wanted to change engine oil in between service like say, every 7k instead of the warranted 15k, should i change differential too?

unfortunately,they charged me $50/bottle. i didnt read this public service announcement before i purchase.

To make you feel better, you bought the expensive one. And the right one . This 'public service announcement' is for the regular SAF-XJ fluid that starts chattering within a few thousand miles. No need to put the same stock crap regardless of price IMO. But I don't plan to get raped with the +FM stock. Hopefully somebody can vouch for one of the fully synthetic 75/140 alternatives.

EVERYBODY KNOWS THAT ALREADY . My pont is if your car makes noise with that fluid, why use it again??? And that oil is A LOT cheaper than the +FM Montreal Red bought, which is the only OEM fluid guaranteed not to chatter.

I rather buy RP or Redline's diff fluid than what I have now, even if free. It's pretty obvious to me that SAF-XJ does not have enough friction modifier, but you're welcome to disagree. I won't use it again. Take care.

Just called a local Mercedes-Benz dealership parts counter, with the same parts number as shown in your picture, and I was quoted $27.50 per bottle.

I had to lie and pretend that my car is a C63 AMG Performance Package :P And even then, they don't even know which car that part number is for So to be sure, I have to "bring it in"

Imagine their surprise when I DO show up....

Locally I was charged $22 for Redline 75W140 gear oil for my 2 annual rear differential fluid changes. I have had no problems with it for 2 years, but if the Castrol is cheaper from Mercedes, I'd do that. Since it's not.... I'll see.

Oh, forgot to mention that the local BMW dealers do not sell bottles yet, still drums. This is Vancouver, BC.

I did not specify whether I wanted the fluid with FM booster. I believe that unless you complain about differential noises, BMW uses non FM booster fluid by default, at least that is what is specified in their repair documentation.

My DCT has stock SAF-XJ and does not make any noise. My 6MT did make noise, however.

The MB fluid is the typical SAF-XJ and does not have FM booster.

Can you please clarify this? Do you know if both with and without FM additive fluids acceptable in the car? I had mine swapped yesterday and they used with FM additive. After the bad news about their price ($55 per bottle - again with FM additive) I found this thread on my mobile at the shop. I referred them to the local MB parts dept who stock the fluid WITHOUT the FM additive for $21/bottle.

From what I know, for earlier model years, the car came w/o FM booster from the factory. Only if you complain about differential noise will they change to fluid w/ FM booster. For later model years they may have changed it from factory, but I cannot confirm.

Just FYI, the OEM BMW fluid and the Castrol are indeed identical in viscosity, 75W140. Next change I will likely go with Redline+FM additive. Although you could probably use the Redline FM additive in the Castrol gear oil, I'll stick with products from the same manufacturer that have been tested together.

^again, the SAF-XJ fluid is the DEFAULT BMW APPROVED fluid for M3's differential (see attached). NOT ALL CARS get the diff noise using the SAF-XJ fluid.

For example, my DCT never made noise with SAF-XJ, but my 6MT did.

this noise you guys talk about how loud is it and what does it sound like? my car sounds like something rubbing in the diff and its not quiet its REALLY loud bmw have tryed this fm booster and said we will change the oil again.

my first diff wasnt locking so they changed it and they never changed the diff oil like they do at 2000kms do you think this could be why its loud?